We installed Airtabs (
Airtab | Aerodynamic Fuel Savers | Welcome) on our Jayco travel trailer in 2014 as a way to control how much trucks pushed us off the road when being passed at high speed. They worked really well, in fact, so well, we could hardly believe it, and our tow car mileage went from 9 mpg to 12 mpg, so when we traded up to our 2012 Thor ACE 29.2 last fall, we thought we should put Airtabs on it as well.
Initially, we drove from Ohio (where we had purchased the MH) back to Virginia and then from Virginia to Florida and back again. That gave us a "baseline" without the Airtabs. Going through the mountains coming back from Ohio we got 6 mpg, and a steady 7 mpg @ 65 mph to and from Florida.
We had hoped the size of our MH relative to the trucks would keep us from being blown to the side of the road, but alas, while better, it still wasn't as good as we had experienced with the Airtabs on our Jayco.
So, I measured the Thor and bought the tabs. They are $2.75 each. I bought 110 black and 70 white. Those are the only colors. If you want to match your exterior, you can paint them with Rust-Oleum plastic paint. All together with shipping, the cost was $518 which included some extras for mistakes. That might seem like a lot, but as I shall show shortly, it's not really.
These are small pieces of plastic in the shape of a "wishbone" with the back side filled in. The large opening faces the front of the vehicle, with the narrow point at the rear. Wind going through the device tends to swirl in a "vortex" pattern causing a slipstream to form behind the vehicle, rather than having the air stream curve around into the low pressure "vacuum" behind the vehicle. This reduces drag and aids fuel economy, but most importantly, it stabilizes the air currents so that passing trucks have minimal effect.
The back side of the air tabs has a very sticky, permanent adhesive. For installation, you take the protective paper off and apply the Airtab to the surface. You only get 1 try as the adhesive is so aggressive, that you don't want to make a mistake and think you can reposition it - you can't!
However, I worked out a simple technique for placement which did allow for positioning and then final placement. It turns out that if you peel the adhesive backing off a little more than 1/2 way and fold it back on itself so that it's sticking out just a little bit from the wide edge, you can place the Airtab and get the alignment very close to perfect. Then, because only the adhesive on the small end is actually touching the MH surface, you can rotate the Airtab making a small adjustment up or down. Once perfect, you hold the Airtab steady while pulling the rest of the backing out from underneath the Airtab, allowing it to then stick in place.
I used "easy off" masking tape to make straight lines for the forward edge and a small block of wood to make sure they were 4" apart. You can also turn one of the Airtabs around and without taking the backing off, use it as a spacer. It's remarkably simple and easy to do. Preparation for an aesthetically pleasing alignment takes longer than actually installing the Airtabs.
The Airtabs are placed 3 per linear foot, i.e. every 4 inches. I installed the black ones on both rear side edges as well as behind the wheel wells. On the roof, I used the white ones on the rear edge and along the sides of various skylight hoods, etc. I also put white ones on our Toad (a 2010 White Scion xB). The entire job took an afternoon.
Do they work? The answer is yes. I have 3 lines of evidence.
First, is the fact that we are no longer blown off the road as much as we were before the Airtabs. Do we know a truck is passing at high speed? Yes, but the push/pull on steering is very mild. However, we also installed a Roadmaster steering stabilizer, and that also helps with better handling so I can't entirely chalk up the improvement to the Airtabs. But they certainly feel like they help.
Second, is the fact that our model is built on a Ford F-53 chassis with a 5 speed automatic transmission. In cruise control, at 65 mph, we normally run just about 2100 rpm on a flat road. Before the Airtabs, at the slightest hint of a hill, our transmission would downshift. If the "hill" was particularly steep, it might downshift 2 gears and send the engine RPM revving into very high, nerve racking ranges. Now, after installing the Airtabs, we've noticed it doesn't downshift nearly as much anymore, particularly on highway overpasses. The engine increases RPM slightly and just labors up the incline, suggesting we have less wind resistance than we used to have. This downshifting problem, by the way, apparently has been corrected in the Ford models built after 2015? where they went to a 6 speed transmission, so if you're thinking about getting a newer MH and it's on a Ford F-53 chassis, go for the 6 speed transmission.
And lastly is gas mileage. We know from several long distance tests (1000+ miles) on the same interstate that before installing the Airtabs, we were getting 7 mpg on the mostly flat terrain between Virginia and Florida towing our Scion at 65 mph using cruise control. After Airtab installation, on the same run, same speed, we were averaging 8 mpg. Big deal, you say. 1 mpg increase!
But looking at in another way, that's a 14% increase in mileage. This summer we plan to drive some 7,000 miles as it's a long way from the East Coast to the West Coast and back again. In the "pre-Airtabs" era, we could have expected to use about 1,000 gallons of gas. With the Airtabs, we can expect to use 7000 / 8 = 875 gallons. If regular gas costs an average of $3.00/gallon (which many people are forecasting might be the case this summer), that will amount to a savings of 125 gallons x $3 = $375. Further, our Scion, which we drive for daily commuting around town gets 28.1 mpg and we're not trying to conserve. This is up from the 26 mpg before installing the Airtabs.
Suddenly, my cost is only $518 - $375 = $143, and that's just for 1 year. Since we will likely do this again in future years, I'm guessing the "payback" is about 2 years. Or put another way, if I hadn't put the Airtabs on, I'd be spending the money (for gasoline) anyway and not have the other benefits of a smoother ride, less nerve racking gear changes, and staying put on the road when trucks, in their great need to hurry, pass us by.
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